1. Field of the Invention
This invention relates to a disk drive apparatus suitable for recording and playing back a disk-shaped recording medium such as, for example, a floppy disk, and in particular to soft landing of a head on said disk-shaped recording medium.
2. Description of Related Art
Conventionally, in a small capacity floppy disk drive FDD of recording capacity 1-2 MB, a low capacity floppy disk cartridge FDC of the type shown in FIGS. 76-80 is used as shown in FIG. 81. When the low capacity floppy disk cartridge FDC is loaded, the center core of a floppy disk 1 is chucked on a disk table 23 inserted in a center core hole 6 of a cartridge 5, and the floppy disk 1 is rotated at a low speed of 200-250 rpm by a spindle 21. A pair of upper and lower magnetic heads 28, 29 are inserted in a pair of head insertion holes 7 in the disk cartridge which are released during loading so that they are in contact with the upper and lower surfaces of the floppy disk 1, and data is recorded and/or played back on the floppy disk 1 while seek and tracking are performed in directions shown by the arrows a, b along scanning centers, which are radial lines extending from the center of the floppy disk 1, by the pair of magnetic heads 28, 29 due to a head transport device.
The Applicant has already developed a high capacity floppy disk cartridge HFDC of the type shown in FIGS. 73-75 wherein the recording capacity is increased to 100 MB or more. In this high capacity floppy disk cartridge HFDC, a pair of magnetic heads, which are flying heads, are floated at distances of the order of microns from the upper and lower surfaces of the floppy disk 1 on an air film (i.e., the heads are "flying") while the floppy disk 1 is rotated at a high speed of 3600 rpm or more, and data is recorded and/or played back at high density.
Regarding the floppy disk 1 used in this high capacity floppy disk cartridge HFDC, the data trackwidth can be reduced by high rotation speeds and high density recording, but it is necessary to improve head surface roughness and make the magnetic layer on the floppy disk 1 thinner to improve contact with the head. For this reason, the size of the magnetic powder must be of the order of 0.1 .mu.m and the coating layer must be of the order of 0.2 .mu.m.
In a prior art low capacity floppy disk drive FDD, the low capacity floppy disk cartridge FDC was inserted in a cartridge holder, and when a lock on the cartridge holder was released by a trigger lever, the low capacity floppy disk cartridge FDC was loaded at high speed by the cartridge holder from an unloading position which is a raised position to a loading position which is a lowered position, the floppy disk 1 was chucked on a disk table 23, and an upper and lower pair of magnetic heads 28, 29 were landed with a shock on the upper and lower surfaces of the floppy disk 1. As the coating thickness of the magnetic layer on the floppy disk 1 of the low capacity floppy disk cartridge FDC is very large, there was no need for concern that the magnetic layer would suffer serious damage even if the pair of upper and lower magnetic heads 28, 29 landed on the upper and lower surfaces of the floppy disk 1 with a shock, and no particular problem with regard to safety.
However, the floppy disk 1 used with the high capacity floppy disk cartridge HFDC having a storage capacity of 100 MB or more has a very thin magnetic coating layer, and if a shock occurs when the pair of upper and lower magnetic heads 27, 28 lands on the upper and lower surfaces of the floppy disk 1 during loading, the magnetic layer which is coated thinly on the disk will suffer serious damage leading to problems of quality and durability.